Pest Control St. Louis

Argentine Ant

Latin Name: Iridomyrmex humilis

Features: It is a small, dark-colored ant about 3 mm (1/8 inch) long that invades homes looking for food and water..

Color: dark-colored

Other: It is in addition light to dark brown in color, and it has six legs, as with other insects. The Argentine ants' antennae have twelve segments. The thorax joins the abdomen by a thin pedicel, a thin stalk.

Where can they be discovered? Outdoors in soil, under timber, slabs, debris, mulch, or in branches and cavities of trees and shrubs

Shallow, 1- to 2-inch deep mounds in open, often disturbed habitats, either moist or dry

The most commonplace ant in southern California is the Argentine ant (Iridomyrmex humilis). This ant can likewise be found in the lower eastern US area. According to Wild (2004), this species was originally described in the genus Linepithema by Mayr in 1866; consequently, the right binomial should be Linepithema humile. It is a small, dark-colored ant about 3 mm (1/8 inch) long that invades homes hunting for food and water. They are specifically fond of sweets, but will feed upon practically any food. They love hard boiled eggs and carry small yellow clumps of yolk back to their nest in endless ant columns.

These ants are really well adapted to urbanized areas of the US with mild climates and well-watered gardens. They pose an important threat to native wildlife by upsetting fragile food webs. They are specifically formidable because of their aggressive behavior and the enormous size of their colonies which can literally "team up" with other colonies.

If you live in southern California, you in all probability have seen endless single file columns of uninvited six-legged guests walking through your home. They follow a pre-marked pheromone "scent" trail initially established by scouts who were looking for goodies in your pantry. Although they choose to outdoor life style, they primarily enter houses for food and water. They are fond of sweets, tuna, syrups (even cough syrup), juices, eggs, dead spiders and rodents, puke, faeces and possibly any other living tissue they can find. They are basically scavengers and they play a valuable role in the natural ecosystem–but preferably in Argentina. In hot, dry weather they often times search your home for water, including washroom faucets and drains. I once followed an ant safari into my restroom where they were neatly stacking their precious cargo of tiny eggs inside my toilet tank. They also relish the "honeydew" secretion of aphids, and look after their aphid friends from natural predators. In the fall months as the nights get chilly, they once again seek the warmth and shelter of your cozy home.

The first Argentine ants set foot on U.S. soils in the late 1890's, as coffee ships from Brazil unloaded their cargo in New Orleans. Being prolific breeders and constantly busy, they moved across the southern half of the United States. A single colony might comprise 10,000 female workers, and there could be hundreds of colonies around your house; the complete number of ants could also reach a million. Although they cannot sting, they can bite; yet, they are only about 3 mm long and there tiny mandibles are too small to hurt humans. But, internationally of insects, these ants are truly a living terror. They are very aggressive and readily overtake other ant species, even ants that are much larger and with powerful stings. Argentine ants are relentless and merely outnumber their adversaries until the enemy colony is destroyed. They even attack paper wasp nests under the eaves of a house, forcing the enormous wasps to flee their nests in terror. Even nests of large carpenter bees are no match for these relentless ants. A "killer bee" nest probably couldn't withstand an invasion of Argentine ants. They also will attack bird nests, driving off the mom bird and killing the helpless young. One possible redeeming quality about these little warriors is that they could attack dry- wood (aerial) termite colonies in your home. I have experienced this Lilliputian massacre in a termite infested table in the Palomar School greenhouse.

Most ant colonies are very highly territorial, and will fight different colonies of the identical species. Since Argentine ants in the United States originated from the original colonizers in Louisiana, they're all closely linked with alike DNA. They evidently will accept ants from different colonies as guests of their gigantic family. In point of fact, Argentine ants from different colonies will actually "team up" and attack together in vast swarms. They only outnumber and overpower their enemy.

Argentine ants have become a difficult threat to the coast horned lizard (Phrynosoma coronatum) in southern California. The main food source for these endangered lizards are native harvester ants, particularly the California harvester ant (Pogonomyrmex californicus). I spent a number of years observing this interesting red ant while maturing in San Gabriel Valley, and I am in a position to personally testify that it has a painful sting. As of 2006, this large red ant is seldom seen in urbanized areas of coastal southern California.

California harvester ant (Pogonomyrmex californicus), primary diet of coast horned lizard.

Urbanization has certainly been a factor in the demise of California harvester ants, but an even better factor leading to the elimination of native ants and coast horned lizards is the aggressive Argentine ant. Apparently the horned lizard is not fond of Argentine ants, and it's actually attacked by them in enormous swarms. Colonies of Argentine ants need a damp area to survive, and have not invaded some of the dry habitats where native harvester ants and desert horned lizards (P. platyrhinos) still live. Naturally, they can readily colonize urbanized desert areas inhabited by people. Well-watered gardens with stepping stones and concrete slabs provide the idea living requirements for these ants. In their native Argentina they live under rocks.

Coast horned lizard (Phrynosoma coronatum).

Argentine ants are a terrible nuisance in gardens and orchards as they tend and look after scale insects and aphids. They even carry aphids to the tender buds of your prized roses. In return, the ants consume a sweet secretion from the aphids called "honeydew." In addition, swarms of these ants will invade orchard trees, destroying the fruit crop. This is specially serious in figs (Ficus carica) where the symbiotic pollinator wasps are destroyed.

Metallic green fig beetles (Cotinus texana) gorging themselves inside a fleshy, ripe syconium of the Calimyrna fig (Ficus carica). Although masses of minute, aggressive Argentine ants (Linepithema humile) are likewise foraging in the syconium (white arrow), the beetles are safe by their tough, impervious exoskeleton. These attractive beetles spend their juvenile larval stage in the land, often beneath manure piles, compost and haystacks.

As reported by entomologist David Faulkner, if you have a 10 x10 foot (3 x 3 m ) patio slab, you could have a million or more individuals and perchance 20 or 30 queens. They get along fine because they're all connected with the original colonizers in Lousiana, perhaps from the original gravid (pregnant) female who arrived there. Workers live a month or more as adults, but queens live up to 10 years or more. With other ants, when the queen dies, the one-queen colony dies because no more ants are being produced. With multi-queen Argentine ants, another queen simply moves in and takes over the role of the deceased queen. In fact, a queen from San Diego would in all likelihood be accepted in a colony elsewhere in California.

Argentine ants (Linepithema humile): A wingless queen and several workers. Although these ants are only 3 mm long, they're very aggressive and quickly annihilate other ant species, even larger ants with powerful jaws and stings. They overpower other species by their sheer numbers. Argentine ants in the U.S. are descendants of original colonizers that entered Louisiana in the late 1890's, as coffee ships from Brazil unloaded their cargo in New Orleans. U.S. populations are so closely associated that different colonies with multiple queens can literally merge together into supercolonies. Image taken with Nikon D-90 and 60mm Micro Nikkor AF-S F/2.8G ED Macro Lens using a Phoenix Ring Flash; hand-held at 640 ISO, F-32, 1/125th sec.

In their native homeland of Argentina, different colonies of Argentine ants are not so friendly to each other because their DNA has developed much greater variation. Neighboring colonies may fight one another, even though they are just 200 yards (200 m) apart. Also the're a great many native predators in Argentina, including fungal parasites and bacteria. The narrow genetic variability that has kept all the California populations on friendly terms may eventually backfire attributable to abnormal inbreeding. Perhaps some day these ants may not have the genetic variability to conform to a changing environment.

How To Control Invasions of Argentine Ants"

Empty your trash often and make sure your home has no crums and food particles that might attract ants. Make certain that food containers are tightly closed, without residual traces of the food on the sides of containers. These ants can even get into screw-top jars without seals. They follow the spiral threads until they're inside!

Avoid using toxic aerosol insecticides inside your house–unless you don't care about your lungs or your bone marrow.

Try spraying a deodorant detergent (Pine Sol